This invention relates to improvements in primary and secondary containers for food and beverages and other consumer products which must be packaged in a sealed condition to protect the product against air, other gases, and/or moisture as well as to provide physical protection during filling, processing, warehousing, distribution, merchandising and customer use.
The invention is extremely well suited for but not limited to the packing of hermetic-packed products which are sensitive to or effected in some adverse way by oxygen or other gases, moisture and/or light. Such products include but are not limited to foods and beverages and other products which hretofore have been hot-filled, cold-packed, frozen, aseptically prepared, pasteurized, retorted, high-temperature, short-time (HT-ST) packed, etc., and otherwise processed. Containers of the invention are also useful for packaging of atmosphere-packed products such as, for example, motor oil, industrial and consumer products, lotions, medicines, wet or dry chemicals, cleaners, cleansers, automotive supplies, and so on.
In the food, beverage and consumer goods packaging industry, the costs associated with conventional containers, whether made of metal, plastic, glass, paperboard, composite, or of single-layer or multilayer materials, are a continually pressing concern because of cost and disposability concerns. Thus, materials cost, vicissitudes of the economy and other major forces of the market place, such as environmental concerns, require extreme reduction in the costs of such containers.
Also, in food and beverage packaging specifically, there has been an increase in the utilization of so-called barrier plastics which provide increased resistance to water vapor transmission and the permeation of various gases. Among such materials which have been made commercially available as single layer (monolayer) or multiple layers for food beverage packaging are polymeric coextruded or laminated sheet and film material such as commercially available under the designations "EVAL" (or "EVOH") (ethylene vinyl alcohol copolymer). High barrier materials of utility are PET film (MYLAR), polyvinylidene chloride (PVDC), and a new class of barrier resins formed of amorphous nylon known as "SELAR PA". Other materials having certain barrier capabilities are high density polyethylene (HDPE), ultra high molecular weight polyethylene (UHMWPE), polypropylene (PP) and oriented polypropylene (OPP), not to mention high impact and other low to medium barrier materials such as polystyrenes (PS) as well as various copolymers such as, for example, acrylonitrile butadiene-styrene (ABS), and high nitrile barrier resins including styrene acrylonitrile (SAN), "BAREX" polymer and polyethylene terephthalate (PET and PETG). Moreover, there are also commercially available a combination of materials with barrier monolayers or employing relatively low barrier materials, such as low density polyethylene (LDPE), HDPE, PP, and HIPS.
One of the greatest economic barriers to the introduction of combinational containers utilizing such plastics has been the requirement that they be constructed of so-called food grade or virgin material. There are, on the other hand, recycled materials not presently used for practical reasons which could be utilized for the making of containers if it were not for the requirement that such containers be utilized in a manner which would expose food and beverage products to their contacting such materials. Thus, for example, one could in theory utilize scrap polymers such as recycled PP and PET, PETG, SELAR and recycled paper-based materials, except that there has not existed heretofore any kind of food container technology or process technology which truly makes practical and/or economic encapsulation of such low-cost materials into a container suitable for packaging and containment of foods and beverages. Nevertheless, the attraction of utilizing such low-cost polymeric materials as well as metal, glass, paperboard and composites is very great because of the extraordinary economy of using such materials, including recycling or re-using such materials, for food and beverage containers as compared with conventional food grade container polymers and specifically the high barrier materials.
As a practical matter, the utilization of the above-noted materials poses also an economic barrier because the formation of containers made by forming container walls of materials with thicknesses adequate to survive the rigors and stresses of processing, filling, warehousing, distribution, merchandising and customer use provides a container which is in fact too expensive for the competitive environment in the domestic and world market for such containers.
Thus there has been long-standing, unresolved problems of the cost in utilizing such expensive materials in adequate thicknesses, in providing such containers with acceptable disposability characteristics, and with capability for recycling and reuse of materials.
From a structural viewpoint, numerous kinds of materials offer advantages for overcoming some of these problems in the construction of food and beverage containers. Although they may lack food-grade properties, and these include paperboard, whether virgin or recycled, various low density plastics, metal, glass and recycled plastic materials such as, for example, the aforementioned PE, PP, PET, PETG and SELAR, etc. However, if such materials are to be utilized to advantage, there must be found a method of inexpensively interposing a barrier between such structural materials and the products to be contained. Paper-based materials have inherently high strength such as to be useful for containment of inner compartments, pouches or linings which enclose a food product, for example. However, such paper-based outer materials are not easily protected from moisture. Heretofore there has been a problem in filling and processing in that packages utilizing paperboard or primarily paper-containing materials have experienced weakening in the strength of the structural components thereof to cause collapse, delamination, deformation and compromise in strength generally.
As compared with other materials of which containers may be formed, paper, such as in the form of layers of wound paperboard, is the least expensive. Since paper is a semisynthetic product made by chemical processing cellulosic fibers, such as from various sources including mainly soft woods but also sometimes hard woods as well as other raw organic materials, including flax, bagasse, straw, etc., it is the ultimately preferred material from an environmental viewpoint. It permits recycling of organic source materials, including waste products, and is both incinerable as well as biodegradable. By contrast, most synthetic resin materials are poorly biodegradable. Metals are not easily incinerated and only low carbon steel is biodegradable through oxidation, whereas aluminum is so expensive and limited in availability that it should not merely be discarded after use. Even though aluminum is being increasingly recycled, a terrible wastage occurs through discarding and wasted burial of aluminum containers which slip through recycling efforts. Paper materials, on a pound-to-pound basis, are also among the strongest available container materials, providing extremely high tensile strength coupled with resilience, as desirable for container manufacturing.
Despite the availability of such materials, it is believed that the packaging industry has failed to address the needs and concerns to which the present invention is directed; the packaging industry has developed around standardized production, concentrating on the high volume, low-cost continuation of existing technologies and endeavoring to protect existing markets.
Although there are a number of different packaging and material technologies, including polymers and resins, composite cans, metal containers, flexible packages, as well as glass, these are all separate bodies of knowledge, materials experiences, science and art. Those in the plastic container industry have not paid sufficient attention to the economics and advantages of combining plastics with other forms of packaging or materials. In the packaging materials industry, there has been a tendency to maintain the status quo because of concerns for labor, capital and costs, and competition.
There is a need for a new generation of low-cost containers capable of providing the full functions which consumers demand or expect from the containers.